A number of filter materials have been suggested for use in cigarette filters, including cotton, paper, cellulose, and certain synthetic fibers. However, such filter materials generally only remove particulate and condensable components from tobacco smoke, and thus are not optimal for the removal of gaseous components, such as volatile organic compounds from tobacco smoke.
Cigarettes incorporating filter elements with adsorbent materials, such as carbon, are disclosed, for example, in U.S. Pat. No. 2,881,770 to Tovey; U.S. Pat. No. 3,353,543 to Sproull et al.; U.S. Pat. No. 3,101,723 to Seligman et al.; U.S. Pat. No. 4,481,958 to Ranier et al. and U.S. Pat. No. 5,568,819 to Gentry et al.; and in European Patent Application No. 532,329.
The use of carbon has been described for filtration applications. See, for example, U.S. Pat. Nos. 4,379,465; 4,412,937; 4,700,723; 4,753,717; 4,772,508; 4,820,681; 4,917,835; 4,933,314; 5,059,578; 5,191,905; 5,389,325; 5,510,063; 5,543,096; 5,632,286; 5,685,986; 5,732,718; 5,744,421; 5,820,967; 5,827,355; 5,846,639; 5,914,294; 5,972,253; 6,030,698; 6,090,477; 6,207,264; 6,214,204; 6,257,242 and 6,258,300; and the publications T. D. Burchell et al., “A Novel Process and Material for the Separation of Carbon Dioxide and Hydrogen Sulfide Gas Mixtures”, 1997, Carbon, 35:1279-94; T. D. Burchell et al., “Passive CO2 Removal Using a Carbon Fiber Composite Molecular Sieve”, Energy Conversion and Management, 1996, 37:947-54; and T. D. Burchell et al., Proceedings of 23rd Biennial Conference on Carbon, American Carbon Society, 1997, p. 158.
Yet, despite these developments, there is a continued interest in improved filters and methods for filtering gases.